Exhaust gas recirculation (EGR) systems are well known in the art per se and are used for controlling the generation of pollutant gases and particulate matter in internal combustion engines. EGR systems recirculate the exhaust gas into the intake air supply of the engine. The exhaust gas that is reintroduced into the engine reduces the concentration of oxygen in the intake air which reduces the maximum combustion temperature within the cylinders and slows down the chemical reaction of the combustion process, which reduces the formation of nitrous oxides.
A problem with existing EGR systems is poor or less effective mixing and distribution of the exhaust gas and the fresh intake air. This causes problems with smoke and unwanted emissions. The use of EGR-distribution rails on modern vehicles improves the EGR-distribution but current systems are inherently hard or impossible to tune for multiple operational points of the internal combustion engine. This normally means that the distribution rail is optimized for one driving point or operational point only and that the engine control unit simply inactivates EGR-function in other operational points. Hence there is a need for EGR-systems that may easily tuned for optimum EGR-performance in multiple operational points of the engine.